1. Field of the Invention
The present invention relates to organic light emitting display devices. More particularly, the present invention relates to packaging of organic light emitting display devices.
2. Description of the Related Art
Recently, organic light emitting displays (OLED) that use organic light emitting diodes are spotlighted.
The organic light emitting displays are spontaneous emission displays that electrically excite organic compounds to emit light and can be driven at a low voltage, can be easily made thin, and have a wide view angle and high response speed.
The organic light emitting display includes a plurality of pixels that include Organic light emitting diodes that are formed on a substrate and thin film transistors (TFT) for driving the Organic light emitting diodes. The Organic light emitting diodes are sensitive to oxygen and moisture. Therefore, a sealing structure in which the oxygen and moisture are prevented from penetrating by covering a deposition substrate with a metal cap coated with an absorbent or a sealing glass substrate is provided.
A method of coating a glass substrate with a frit to seal up an OLED is disclosed in U.S. Pat. No. 6,998,776. As disclosed in the U.S. Pat. No. 6,998,776, a gap between a substrate and a sealing substrate is completely sealed up using the frit so that it is possible to effectively protect the OLED.
Although the frit of U.S. Pat. No. 6,998,776 does seal the gap between the substrates, there can be problems with the lifespan of the seal. The adhesion force provided by the frit between the substrates may deteriorate such that the substrates may become separated. In such a case, the oxygen and moisture may penetrate into the OLED to deteriorate the life span and the emission efficiency of the organic light emitting display. What is needed is a method of adhering the substrates that provides improved reliability and a longer lifespan.
The discussion in this section is to provide a general background of organic light-emitting display devices and is not an admission of prior art.